1. Field of the Invention
This invention relates to a composite magnetic component comprising a magnetic member or a magnetic base member, a portion of which has a non-magnetic region formed as a modified magnetic property section having the magnetic property modified through modification of physical property effected in the entire thickness thereof, and a method of manufacturing such composite magnetic component.
More specifically, the present invention relates to a yoke component with integral soft magnetic and non-magnetic parts in a magnetic application product, a portion of which being provided with a non-magnetic region formed as a magnetic flux blocking section having a magnetic flux blocking property through modification of physical property and a method of manufacturing such yoke component having the integral soft magnetic and non-magnetic parts provided with a magnetic flux blocking section.
Further, the present invention relates to a composite magnetic component for magnetic flux transmission, which can effectively transmit magnetic flux or other magnetic signals output from a magnetic scale or other magnetic signal output members to a magnetic sensor, as well as a method of manufacturing such composite magnetic component for magnetic flux transmission and a magnetic sensor device including such composite magnetic component for magnetic flux transmission.
2. Description of the Prior Art
FIGS. 1 and 2 show a yoke component with a magnetic flux blocking section in a magnetic application product and a method of manufacturing the same in a first prior art. In this prior art, a separate member H of a non-magnetic material corresponding to a non-magnetic region is welded by butt welding to a soft magnetic member M constituting a yoke.
In the yoke component and the method of manufacturing the same in the first prior art, since the non-magnetic separate member H is welded to the soft magnetic member M constituting the yoke, there is a notch K in each section of welded portion Y as shown in FIG. 1 to result in the reduction of the mechanical strength. In addition, the manufacture of such yoke components involve many steps and leads to a high cost.
FIGS. 3 and 4 show a fuel seal in an solenoid valve in a second prior art. This seal is effected with a resin member J enclosing a coil C and an O-ring O of rubber fitted in a recess formed in the resin member.
In the solenoid valve in the second prior art, since the seal is effected with the resin member J enclosing the coil C and the O-ring O, there is a problem of insufficient sealing that results when the pressure is increased to enhance the performance.
FIG. 5 shows a composite magnetic component for magnetic flux transmission in a third prior art. This component is disposed between a magnetic scale member SJ as an output member B having a magnetic scale and a magnetic sensor S, and transmits magnetic flux (as shown by dashed lines in FIG. 5). As to this component, a member HB of a non-magnetic material corresponding to a non-magnetic region is bonded to a soft magnetic base member SM, as shown in FIG. 6 or 7.
In the composite magnetic component for magnetic flux transmission in the third prior art, since the member HB of the non-magnetic material is bonded to the base member SM, there is a notch SK in each bonded section BD as shown in FIG. 8 to result in the deterioration of the mechanical strength.
FIG. 9 shows a magnetic component for magnetic flux transmission in a fourth prior art. In this instance, not only a portion of the component corresponding to a magnetic sensor but also the entire component is constituted by a non-magnetic material HB.
Since the composite magnetic component for magnetic flux transmission in the fourth prior art is entirely constituted by the non-magnetic material, there is a problem in the aspect of the cost. For instance, the cost in case of SUS 304 is about four times as much as that of a usual iron type material.